Some of the most important fossils from the Green River Formation are the
vertebrates. Among these are the oldest known bat, bird fossils assigned
to extinct families, snakes, turtles, and crocodylians.

Perhaps the best known vertebrate fossils are the spectacular fish. Gars,
rays, herring, and an array of bony fish in all sizes have been found preserved
in Green River strata.

This is a cast from the original specimen. Even so, you can see the fine
detail with which the entire skeleton is preserved. In addition to
recognizable groups, two entirely extinct families of birds were discovered
from Green River.